1. Field of the Invention
The present invention relates, for example, to a welding power supply apparatus, and particularly to a welding power supply apparatus provided with a fan for air cooling.
2. Description of Related Art
JP 2008-229644A discloses an example of a conventional welding power supply apparatus. The power supply apparatus disclosed in the document includes a plurality of electronic components, an air path extending longitudinally, and a fan that blows air draft into this air path. The plurality of electronic components are arranged along a side wall of the air path, and the fan is provided at one end of the air path. Air draft that has been blown into the air path by the fan blows out from an exit provided at the other end of the air path, while drawing heat away from the electronic components. As compared to electronic components that do not tend to generate heat (for example, a chip-type semiconductor device and the like), electronic components that tend to generate heat (for example, a transformer, a reactor, and the like) are arranged closer to the fan such that they can be efficiently air-cooled.
In the case of using such a power supply apparatus in an environment with a lot of dust, such as a factory, dust tends to enter the air path and accumulates inside the air path. For this reason, it is necessary to perform a dust removal operation such as an operation that involves aiming an air blow gun at the interior of the air path from the exit thereof and periodically blowing the dust present inside the air path away by jetting compressed air.
In the case of the above-described conventional power supply apparatus, air draft flows a relatively long distance from one end of the air path to the other end. Therefore, the conventional power supply apparatus has a drawback in that any electronic components located away from the fan cannot be easily cooled. It also has a drawback in that the flexibility of arrangement of electronic components is not very high since a plurality of electronic components that are to be cooled need to be arranged in such a manner that those with a higher likelihood of generating heat are arranged closer to the fan. Moreover, during a dust removal operation, compressed air that has been jetted to the interior of the air path tends to directly strike the fan located at one end of the air path, which may cause the fan to be rotated in reverse at high speed and be damaged.
In addition, the above-described conventional power supply apparatus has only a single air path. When a plurality of electronic components having different heat-generating properties are arranged in that air path, this arrangement significantly affects the temperature and the flow of air draft, resulting in the problem that each of the electronic components cannot be cooled efficiently.
JP 2009-298116A discloses another example of a conventional power supply apparatus. The power supply apparatus disclosed in the document contains, inside a welding power supply portion, an electronic component that is to be cooled, and a fan is provided in a front surface portion of the welding power supply portion. The welding power supply portion is housed in a casing, and thereafter the front surface portion is covered by a front plate. The front plate is provided, at its portion located in front of the fan, with an opening for introducing outside air. With this power supply apparatus, the opening is located in front of the fan, and therefore dust floating in the vicinity of the opening can easily be sucked in by the fan, resulting in the problem that dust can easily enter the welding power supply portion.